1. DomName('ShadowRoot.getElementsByClassName')
  2. DocsEditable()
List<Node> getElementsByClassName(String className)

Source 

@DomName('ShadowRoot.getElementsByClassName')
@DocsEditable()
List<Node> getElementsByClassName(String className) => wrap_jso(_blink.BlinkShadowRoot.instance.getElementsByClassName_Callback_1_(unwrap_jso(this), className));